Nekton

Preliminary modeling of tsunami potential in the Tanimbar Islands

Sun, 27 Apr 2025 00:00:00 +0000

The Tanimbar Islands are an area of high tectonic activity and are part of the outer arc island chain formed by subduction in the Banda zone. The presence of the Sorong Fault and Tanimbar Fault around the Tanimbar Islands also affects the level of vulnerability to earthquakes and tsunami hazards. The purpose of this study was to predict the tsunami potential and affected area of the Tanimbar Islands. The method of analyzing the height data and predicting the affected area used COMCOT v1.7 software. Model simulations were performed on the domain layer by using linear equations. Earthquake and fault parameter data were obtained from the USGS website using historical earthquakes dated January 10, 2023. Bathymetry data were obtained from the GEBO website at a resolution of 15-arcsecond (464 m). The model simulation results show that the initial wave height value marked by the red contour is 0.22 m and the lowest low tide value marked by the blue contour is -0.4 m. Based on these results, the tsunami potential in the Tanimbar Islands is not dangerous, as the potentially affected areas in the study area are Selu Island, Woluaru Island, Wotap Island, and Molu Island, as well as the small islands in the western part. The simulation results demonstrate the importance of research related to tsunami hazards that may occur in the future so that appropriate mitigation can be planned for the existence of small islands around the Tanimbar Islands.

Analysis of the suitability and carrying capacity of coral reef ecotourism for diving tourism on Karampuang Island, Mamuju District, West Sulawesi Province

Arwin Arwin, Fanella Muhammad Askin Putra, Jalil Machfud Hapitah — Sun, 04 May 2025 00:00:00 +0000

Nature tourism is a visit to a tourist spot that is still relatively natural, so it is minimal due to disturbance or pollution. The research objective was to analyze the cover condition, damage status of coral reefs, reef fish species diversity, and carrying capacity of the area for diving tourism development in the Karampuang Island Waters. The research was conducted from August 07 to October 07, 2020, in Karampuang Island, Mamuju Regency, West Sulawesi Province. The land suitability analysis used in the research was guided by the formula and matrix of land suitability for diving tourism and analysis of the area's carrying capacity. Based on the calculation of the research results, live coral cover, with an average of 27.26%, was included in the medium category. With a reef fish diversity index found at four stations ranging from 2.97-3.16, with 12 families, 33 species, and 557 individual fish, Karampuang Island is suitable for the development of diving tourism; the entire research area qualifies as marine tourism, especially diving tourism groups with suitability categories between 88.89-100% and the area reaches 52,740 m2 so that it can accommodate as many as 113 tourists per day.

Utilization of shrimp head powder to enhance color performance and growth of multicolor betta fish (Betta splendens)

Thu, 08 May 2025 11:34:19 +0000

Betta splendens is an ornamental fish with a variety of color variations, which is one of the main factors determining its selling value. One of the variants of hippopotamus, which is currently in great demand by ornamental fish enthusiasts, is the multicolor hippopotamus. During maintenance, cupang fish often experience a decrease in color quality caused by internal and external factors. One of the efforts to improve color quality is to supplement the feed with ingredients rich in pigments, such as shrimp head flour (TKU), which contains carotenoids. This study aimed to improve the brightness and color performance of hippopotamus by adding shrimp head meal to commercial feed. The method used was a completely randomized design (CRD) with four treatments, namely, control, 5% TKU, 10% TKU, and 15% TKU, each with three replicates. The research procedure included the preparation of shrimp head meal, mixing feed with TKU, fish rearing, and observation of changes in color brightness, weight and length growth, survival rate, and water quality. The results showed that the utilization of shrimp head meal supplemented into the feed improved the performance of brightness and color patterns in multi-colored cupang fish, including length gain during the treatment, with optimum results shown in the 10% TKU treatment.

Relationship between fish consumption and nutritional status and learning achievement of vocational high school students in Mejayan Village, Madiun Regency

Haendra Kusuma Putra Ashad, Agnes Puspitasari Sudarmo, Abdul Kohar Mudzakir — Sun, 11 May 2025 10:56:48 +0000

Vocational High School (SMK) is a secondary school that aims to produce quality human resources for those who are ready to work at a productive age. SMK-level schools are inhabited by teenage children at the age–15-17 years. Teenagers at that age need adequate nutritional intake, both in quality and quantity, for their growth and development, both in terms of health and non-health. Fish is a food ingredient with a variety of health and non-health benefits. The health benefits of fish are in the form of good nutritional status, while in the non-health aspect, it improves cognitive aspects in the form of learning achievements at school. This study aimed to investigate the relationship between fish consumption, nutritional status, and learning achievement among vocational students in Mejayan Village. The study used a cross-sectional design with 177 students, and data were collected through questionnaires, anthropometric measurements of IMT/U, food recall 1 × 24 hours, and report card scores. Data analysis using the Chi-Square method The results showed that the fish consumption level of vocational high school students in Mejayan Village was low at 8.18 kg/capita/year and there was no significant relationship with nutritional status (p=0.911) or learning achievement (p=0.422). The absence of a relationship between the two variables may be due to factors other than fish consumption that influence the results. Based on this research, education on the importance of fish consumption for students is needed to increase the benefits of their nutritional and cognitive status.

Composition and diversity of drift gillnet catches landed at PPI Cikidang Pangandaran

Gilar Budi Pratama, Khoerunnisa Nurani — Mon, 12 May 2025 16:20:34 +0000

Cikidang Fishing Port is one of the fishing ports that plays an important role in capture fisheries in Pangandaran, with drift gillnet as the main fishing gear. The high use of this tool encourages the analysis of the diversity and composition of the catch to assess fishery productivity and maintain resource sustainability. This study aimed to analyze the composition and diversity of drift gillnet catches landed at the PPI Cikidang Pangandaran. The methods used include the calculation of production amount and value, Catch Per Unit Effort, percentage of catch composition, and diversity index. The data analyzed were obtained from the Cikidang PPI statistical report during the 2019-2021 period. The results showed that white pomfret (Pampus argenteus) was the most dominant species in the catch, with an average contribution of 26.4% per year, whereas yellow mackerel (Selaroides leptolepis) had the least catch (only 0.62% per year). The catch diversity index showed a value of 2.77 in 2019, 2.19 in 2020, and 2.21 in 2021, which falls into the medium category. Habitat conservation efforts and increased awareness of fishermen are also needed so that fishery resources in the Cikidang Fishing Port remain sustainable and productive in the long term.

Tropical cyclone Lili in the Banda Sea, Indonesia: formation, development, and oceanic interaction

Moksen Siwasiwan, Simon Tubalawony, Yunia Anganetjie Noya — Tue, 13 May 2025 13:52:08 +0000

The Banda Sea serves as Indonesia's central region of water mass circulation and receives water flows from the Pacific Ocean, Indian Ocean, and South China Sea. This unique position facilitates significant interactions between the atmosphere and the ocean. This study aims to assess the dynamic factors supporting tropical cyclone Lili's growth in the Banda Sea. This study uses data from the Climate Data Store (CDS) and Marine Copernicus for May 4-12, 2019. The results show atmospheric dynamics, including the presence of low-pressure zones, high air humidity, and other meteorological factors that support the formation and movement of cyclones. During the study period, oceanographic conditions showed varying wind directions from various sources, hindering the wave formation process. Current patterns were observed moving from Australia through Tanimbar waters towards the Banda, Seram, and Timor Seas. In addition, eddy formation was found in Wetar waters, with downwelling processes occurring in the Banda Sea, while upwelling was detected in eastern Seram waters.

Thermal front dynamics and the correlation with Sardinella Lemuru catches in the Bali Strait

Hendrik Anggi Setyawan, Bogi Budi Jayanto, Ayu Retno Wardhani — Tue, 20 May 2025 23:06:19 +0000

The Bali Strait is a marine area rich in lemuru fish (Sardinella lemuru), making it a potential fishery commodity in Indonesia. Sustainable management of lemuru fish populations in the Bali Strait is crucial for maintaining ecosystem balance and ensuring the sustainability of the fishing industry in the region. This study aimed to identify the thermal fronts in the Bali Strait and the relationship between thermal fronts and lemuru fish production. This research was conducted using monthly sea surface temperature and surface current data from the CMEMS for the year 2023, along with lemuru production data from PPN Pengambengan. An edge detection method was employed to determine thermal fronts. The results showed that sea surface temperatures ranged from 24.9°C to 29°C. The meridional movement from North to South dominates the Bali Strait surface currents. Thermal fronts were observed throughout the year, with weak fronts dominating during the west monsoon and transition season I, whereas strong fronts intensified during the southeast monsoon. However, the correlation between thermal fronts and lemuru catch was very weak (r=-0.047442), suggesting that thermal fronts are not the primary factor influencing lemuru catch.